How to use it
- Choose the format you have: decimal or DMS, UTM, or MGRS.
- Paste the value and press Convert, or click the map, or use your location.
- Read the same point in every format. Click a value to copy it. Drag the pin and the formats follow.
5 practical uses
- Convert a GPS reading into the grid reference a paper map uses.
- Enter a coordinate from a chart or a survey into a web map.
- Change the format for a form that wants DMS or decimal degrees.
- Translate an MGRS grid reference into a point for a map.
- Check a coordinate typed in one format against another.
The maths behind it
DMS: the degrees are the integer part, the minutes the integer part of the remainder times 60, the seconds the rest times 3,600. UTM uses the transverse Mercator projection of the WGS84 ellipsoid (a = 6,378,137 m, f = 1/298.257223563) in 6° zones with a scale factor of 0.9996 at the central meridian, computed with the Krüger series; the easting has 500,000 m added and the southern northing 10,000,000 m. MGRS writes the UTM zone and band, then the 100 km square letters and the metres within it.
The formats
- Decimal degrees (DD):
51.507400, -0.127600. Latitude first; south and west are negative. Six decimals is about 10 cm. - Degrees, minutes, seconds (DMS):
51°30′26.6″N 0°07′39.4″W. Sixty minutes to a degree, sixty seconds to a minute. - Degrees, decimal minutes (DDM):
51°30.444′N 0°07.656′W, the form used by GPS receivers and at sea. - UTM: zone, hemisphere or latitude band, easting and northing in metres, such as
30U 699330 5710164. The Earth is cut into 60 zones of 6° of longitude, each mapped flat, so distances measure in metres with a ruler. - MGRS: the military grid, UTM written as zone, band, a 100 km square pair of letters and the metres within it:
30UXC9933010164. Fewer digits mean a bigger square.
All on WGS84, the datum of GPS and of web maps. Converting from a national grid or an old datum needs a datum shift this tool does not do.